It is well known to catalyze the alkylation of aromatics with a variety of Lewis or Bronsted acid catalysts. Typical commercial catalysts include phosphoric acid/kieselguhr, aluminum halides, boron trifluoride, antimony chloride, stannic chloride, zinc chloride, onium poly(hydrogen fluoride), and hydrogen fluoride. Alkylation with lower molecular weight olefins, such as propylene, can be carried out in the liquid or vapor phase. For alkylations with higher olefins, such as C16+ olefins, the alkylations are done in the liquid phase, often in the presence of hydrogen fluoride. Alkylation of benzene with higher olefins may be difficult, and typically requires hydrogen fluoride treatment. Such a process is disclosed by Himes in U.S. Pat. No. 4,503,277, entitled “HF Regeneration in Aromatic Hydrocarbon Alkylation Process,” which is hereby incorporated by reference for all purposes.
These alkylated aromatics are then further reacted to produce sulfonates (i.e., surfactants) that may be used in enhanced oil recovery from various oil-containing reservoirs. It has been discovered that not all surfactants work in all reservoirs the same. Some surfactants, based upon their molecular structure, give better oil recovery in reservoirs that have a reservoir temperature of at least 185 degrees F., a 36 degree API, a brine salinity of 2500 ppm and brine dissolved solids (TDS) or 3000 ppm.